Flower Architecture Research Articles

Cloning and functional analysis of five TERMINAL FLOWER 1/CENTRORADIALIS-like genes from Hevea brasiliensis.

Five TERMINAL FLOWER 1 (TFL1)/CENTRORADIALIS (CEN)-like genes were isolated and characterized from rubber tree (Hevea brasiliensis). All genes, except HbCEN1, were found to have conserved genomic organization, characteristic of the phosphatidyl ethanolamine-binding protein (PEBP) family. Overexpression of all of them delayed flowering and altered flower architecture compared with the wild-type (wt) counterpart. In addition, as premature-flowering of the terminal bud was successfully overcome in the tfl1-1 mutant of Arabidopsis, all these genes have a potential function similar to TFL1. Quantitative reverse transcriptase-polymerase chain reaction analysis showed higher expressions of HbCEN1 and HbCEN2 in the shoot apices and stems of both immature and mature rubber trees than in reproductive organs. HbTFL1-1 and HbTFL1-2 expression was confined to roots of 3-month-old seedlings and HbTFL1-3 was significantly higher in the shoot apices of these seedlings. These results suggested that HbCEN1 and HbCEN2 could be associated with the development of vegetative growth, whereas HbTFL1-1, HbTFL1-2 and HbTFL1-3 seem to be mainly related with maintenance of juvenility. In addition, four of the five genes displayed variable diurnal expression, HbTFL1-1 and HbTFL1-3 being mainly expressed during the night whereas HbCEN1 and HbCEN2 showed irregular diurnal rhythms.

Solar-Light-Driven Improved Photocatalytic Performance of Hierarchical ZnIn2S4 Architectures.

In the quest for developing novel narrow band gap semiconductor materials, the research in metal chalcogenides has gained a strong attraction. In the present investigation, a surfactant-free hydrothermal route has been followed to design hierarchical self-assembled flower-like ZnIn2S4 structures through control over precursor concentration and hydrothermal processing parameters. Uniform hexagonal marigold flower-like ZnIn2S4 architectures (∼4 μm) were formed with self-assembly of petals (thickness ∼8–12 nm) forming rose-like structures and finally forming marigold flowers in 24 h duration. The hierarchical ZnIn2S4 flower structure has been used as photocatalysts for the degradation of dye and chlorinated phenols. Photodegradation demonstrates that the high surface area from the porous flower architecture (∼72 m2/g) with an enhanced visible light absorption giving low band gap energy (2.15 eV) is responsible for higher photocatalytic performance. Complete degradation of the organic pollutants has been observed within 90 min in the presence of natural sunlight. To understand the participating reactive species contributing to degradation, scavenger studies were performed for deducing the plausible photocatalytic degradation pathways. This study might open new insights into the design of novel hierarchical structures.

Hierarchical Design of CuS Architectures for Visible Light Photocatalysis of 4-Chlorophenol.

Hydrothermal-assisted CuS hierarchical architectures were grown in the presence of anionic sulfur sources, and the investigation of their degradation efficiency for a pesticide 4-chlorophenol (4-CP) under visible light irradiation was carried out. The dissociation of S2– from the sulfur compound governs the nucleation of CuS followed by a specific pattern of growth to produce different morphologies. The self-assembled covellite spherical CuS flower architecture assembles in the presence of thiourea and exhibits the highest photodegradation activity. The open architecture of ∼2.3 μm spherical CuS flowers consisting of a ∼100 nm thick sheet encompasses a comparatively high surface area and particle growth along the (110) plane that facilitates more active sites for catalytic activity enhancement. The catalyst loading for 4-CP degradation has been optimized, and a detailed trapping mechanism has been explored.

Lateral and “Vertico-Lateral” Cave Dwellings in Haddej and Guermessa: Characteristic Geocultural Heritage of Southeast Tunisia

Southeast Tunisia is known for different types of cave dwellings developed for centuries on the Matmata-Dahar plateau. Their formation takes into account the geological and geomorphological context of the sites. They thus provide an interesting example of geoheritage on which was developed an important cultural and architectural heritage. An interdisciplinary research—crossing geomorphological and historical/architectonical approaches—was carried out in two sites: Haddej and Guermessa. The Haddej site belongs to the Matmata area located in the northern part of the plateau. It is characterised by cave dwellings dug vertically and then laterally in the Quaternary aeolian silty deposits filling the valleys that dissect the plateau surface, which corresponds to the backslope of a cuesta. This geomorphological context gives a “vertico-lateral” cave dwellings in “Flower architecture”. The Guermessa site belongs to the Tataouine region, located in the southern part of the plateau. Cave dwellings were dug laterally in alternations of limestone, clay, marl and dolomite strata that appear on witness buttes and outliers slopes. The result is lateral cave dwellings in “Foot architecture”. Both sites offer favourable conditions for geomorphological study. They exhibit a wide range of structural landforms within the monocline structure and their surroundings present a variety of forms and Quaternary formations. These geomorphosites were assessed using the method developed by the University of Lausanne, which allowed us to assign them a strong scientific, aesthetic, cultural, educational and tourist value. Proposals for their tourist promotion were then made taking into account the lack of maintenance that reduces their cultural and tourist value.

Architecture of 3D ZnCo2O4 marigold flowers: Influence of annealing on cold emission and photocatalytic behavior

The present work demonstrates the field emission characteristics and photocatalytic behavior of ZnCo2O4 marigold flowers synthesized via a facile hydrothermal method. The effect of annealing of these 3D porous hierarchical nanostructures on field emission and photocatalytic performances is studied. When compared with the as-synthesized sample, annealed ZnCo2O4 exhibits a ∼2-fold improvement in photocatalytic activity for methylene blue (MB) degradation under visible light irradiation. The turn-on, threshold fields and high emission current densities are also strongly influenced as a result of annealing. The turn on field required to draw an emission current density of ∼1 μA/cm2 is found to be ∼2.4 and ∼1.8 V/μm for as-synthesized and annealed ZnCo2O4 marigold flowers, respectively. Field-emission measurements demonstrate remarkably large field enhancement and better stability for annealed samples. The X-ray diffraction and Raman analysis reveal that annealing improves the crystallinity and also help to remove the structural defects in ZnCo2O4. The enhancement in the field emission and photocatalytic activity of annealed ZnCo2O4 marigold flowers is attributed to the modification of electronic properties as a result of dehydration, crystallite growth and reduced surface defects/impurity phases.

Identification and expression analysis of receptor-like kinase gene ERECTA in mycoheterotrophic plant Monotropa hypopitys

The precise spatial-temporal coordination of cell division and differentiation is necessary for the correct formation of tissues, organs, and the organism as a whole. This coordination has been implemented by the intercellular communication mediated by signaling molecules and receptors that selectively recognize them. Membrane receptor kinases of ERECTA family regulate inflorescence and flower structure, the formation of root epidermis and adaptation responses. The characterization of the ERECTA genes of flowering plant pinesap Monotropa hypopitys with unique development features can enrich the knowledge about the kinase ERECTA functions and conserved development processes with their participation. Transcriptomic and genomic search with the subsequent structural-phylogenetic analysis identified the mRNA of a gene of serine-threonine kinase receptor with leucine-rich repeats of MhyERL1, which is the only ortholog of the ERECTA family kinases of pinesap. A quantitative analysis of the MhyERL1 gene transcripts has revealed its expression in all analyzed pinesap tissues with maximum levels in the flowers. MhyERL1 is probably involved in defining the inflorescence and flower architecture, and the formation of the pinesap root epidermis. The cascades involving ERL1 are apparently conserved. The exception are pathways associated with the development of above-ground vegetative structures, and the immune response to fungal pathogens probably lost in the process of the pinesap adaptation to unfavorable environmental conditions.

Synthesis of δ-MnO2 with nanoflower-like architecture by a microwave-assisted hydrothermal method

By a microwave-assisted hydrothermal method, nanoflower-like δ-MnO2 was prepared for application in supercapacitors as electrode material. The characterization results indicated that the obtained architecture had the characteristics of electrode materials with high electrochemical performance. The flower architecture provided the channel surrounded by the nanosheets-like petals for the fast transfer of electrolyte ions. The thin thickness of nanosheets minimized the diffusion distance of electrolyte ions beneath the surface of material particles. The two advantages of the material guaranteed the high performance of material. It presented specific capacitance of 328 F g−1 at 5 mV s−1 in 1 M Na2SO4 aqueous solution within a wide potential window of −0.5~1.0 V. During cycle stability test, the capacitance of material still remained 89% of its initial value after 5000 charge–discharge cycles. These results demonstrated that the nanoflower-like δ-MnO2 could be applied as high performance electrode material. MnO2 with different crystallographic forms and architectures was prepared by normal hydrothermal and microwave-assisted hydrothermal methods, respectively. The α-MnO2 prepared by normal hydrothermal method presented architecture of nanobundles and the δ-MnO2 prepared by microwave-assisted hydrothermal method exhibited architecture of nanoflower. The results of electrochemical measurements indicated that δ-MnO2 had the higher performance than α-MnO2 due to its unique nanoflower architecture.

The genome and transcriptome of Phalaenopsis yield insights into floral organ development and flowering regulation.

The Phalaenopsis orchid is an important potted flower of high economic value around the world. We report the 3.1 Gb draft genome assembly of an important winter flowering Phalaenopsis ‘KHM190’ cultivar. We generated 89.5 Gb RNA-seq and 113 million sRNA-seq reads to use these data to identify 41,153 protein-coding genes and 188 miRNA families. We also generated a draft genome for Phalaenopsis pulcherrima ‘B8802,’ a summer flowering species, via resequencing. Comparison of genome data between the two Phalaenopsis cultivars allowed the identification of 691,532 single-nucleotide polymorphisms. In this study, we reveal that the key role of PhAGL6b in the regulation of labellum organ development involves alternative splicing in the big lip mutant. Petal or sepal overexpressing PhAGL6b leads to the conversion into a lip-like structure. We also discovered that the gibberellin pathway that regulates the expression of flowering time genes during the reproductive phase change is induced by cool temperature. Our work thus depicted a valuable resource for the flowering control, flower architecture development, and breeding of the Phalaenopsis orchids.

Architecture of 2D MoS2 nanosheets and 3D CdMoS4 marigold flowers: Consequence of annealing on field emission performance

Herein, we report the field electron emission investigations on template free solvothermally synthesized layered MoS2 nanosheets as well as novel phase of CdMoS4 nanoflowers at the base pressure of ∼1 × 10−8 mbar. The turn-on field, threshold field and maximum emission current densities for both MoS2 and CdMoS4 are strongly influenced by thermal annealing in inert atmosphere. The turn on field, required to draw emission current density of 1 μA/cm2 is found to be 5.8 and 3.2 V/μm for pristine and annealed MoS2 at 400 °C. In case of as prepared and annealed CdMoS4 sample the turn on field values are found to be ∼6.2 and 5.0 V/μm, respectively. The emission current versus time (I–t) plot measured at the preset current values of ∼1 μA for pristine and annealed sample indicates stable operation of the emitter. The emission current fluctuations for annealed sample are observed to be less as compared with the pristine sample due to conditioning of the emitter, thereby showing highly stable nature of emitter. Thus, the present result demonstrates the potential of annealed MoS2 nanosheets and CdMoS4 nanoflowers as an emerging materials for micro/nanoelectronics and flat panel field emission display applications.

The Dendrobium catenatum Lindl. genome sequence provides insights into polysaccharide synthase, floral development and adaptive evolution.

Orchids make up about 10% of all seed plant species, have great economical value, and are of specific scientific interest because of their renowned flowers and ecological adaptations. Here, we report the first draft genome sequence of a lithophytic orchid, Dendrobium catenatum. We predict 28,910 protein-coding genes, and find evidence of a whole genome duplication shared with Phalaenopsis. We observed the expansion of many resistance-related genes, suggesting a powerful immune system responsible for adaptation to a wide range of ecological niches. We also discovered extensive duplication of genes involved in glucomannan synthase activities, likely related to the synthesis of medicinal polysaccharides. Expansion of MADS-box gene clades ANR1, StMADS11, and MIKC*, involved in the regulation of development and growth, suggests that these expansions are associated with the astonishing diversity of plant architecture in the genus Dendrobium. On the contrary, members of the type I MADS box gene family are missing, which might explain the loss of the endospermous seed. The findings reported here will be important for future studies into polysaccharide synthesis, adaptations to diverse environments and flower architecture of Orchidaceae.

Fine mapping and candidate gene analysis of a novel PANICLE AND SPIKELET DEGENERATION gene in rice

To better understand the molecular mechanisms that regulate inflorescence and flower architecture, we characterized the rice panicle and spikelet degeneration (psd) mutant, which exhibited small panicles with a reduced number of primary and secondary branches. The psd mutant had few spikelets per panicle, and they were deformed and could not form seeds. The psd mutant had a unique panicle organization phenotype that was not present in other aberrant panicle organization mutants. Genetic analysis revealed that the mutation was controlled by a single recessive gene. A map-based cloning strategy was employed to isolate the PSD locus. The PSD locus was initially located between RM13046 and RM5356 on chromosome 2. Recessive individuals (n = 7307) in F2 mapping populations from two crosses between heterozygous Psdpsd plants and two indica rice varieties, IR28 and 93-11, were used to finely map the PSD locus. The PSD locus was mapped to a 14.6 kb region between two newly developed dCAPS markers, dC7 and dC8, within BAC OJ1115_D03. The candidate regions harbored two ORFs, Os02g0284500 and Os02g0284600. Sequence analysis revealed that only one single amino acid substitution mutation in the Os02g0284500 gene in the candidate region, which altered the predicted three-dimensional Os02g0284500 protein structure. A tetra-primer amplification refractory mutation system-PCR marker, TP-psd, was developed from the psd mutant mutation site. All 7307 homozygote recessive plants in the two F2 populations showed the same band pattern as that of psdpsd. This suggested that Os02g0284500 is most likely the PSD gene. Our results provide a basis for future functional PSD studies.

Flower bouquet variation in four species of Crocus ser. Verni.

Flowering plants employ a wide variety of signals, including scent, to attract pollinators. The aim of this work was to examine whether flower volatiles in four closely related Crocus species are linked to species divergence and to the current knowledge on their pollination syndromes. Fragrances of freshly opened flowers in Crocus etruscus, C. ilvensis, C. neglectus, and C. vernus, all belonging to ser. Verni, were analyzed using GC/MS. Results coincide with present knowledge about systematic relationships among taxa. The four species fall into two main fragrance types, based on similarities of their volatile compounds. In C. etruscus, C. ilvensis, and C. neglectus, oxygenated monoterpenes (lilac aldehyde B and A) are most abundant, while C. vernus has a fragrance rich in monoterpene hydrocarbons (α-pinene and limonene). Our results point towards outcrossing mating strategies for C. etruscus, C. ilvensis, and C. neglectus, whose volatile compounds are known as pollinator attractants. This is in line with their flower architecture, showing a style of variable height, often overtopping stamens. On the other hand, a self-pollination strategy was repeatedly suggested in the literature for C. vernus, marked by flowers with the style deeply inserted in the stamens and also by a completely different flower bouquet.

Mapping genes governing flower architecture and pollen development in a double mutant population of carrot.

A linkage map of carrot (Daucus carota L.) was developed in order to study reproductive traits. The F2 mapping population derived from an initial cross between a yellow leaf (yel) chlorophyll mutant and a compressed lamina (cola) mutant with unique flower defects of the sporophytic parts of male and female organs. The genetic map has a total length of 781 cM and included 285 loci. The length of the nine linkage groups (LGs) ranged between 65 and 145 cM. All LGs have been anchored to the reference map. The objective of this study was the generation of a well-saturated linkage map of D. carota. Mapping of the cola-locus associated with flower development and fertility was successfully demonstrated. Two MADS-box genes (DcMADS3, DcMADS5) with prominent roles in flowering and reproduction as well as three additional genes (DcAOX2a, DcAOX2b, DcCHS2) with further importance for male reproduction were assigned to different loci that did not co-segregate with the cola-locus.

The role of WOX genes in flower development.

WOX (Wuschel-like homeobOX) genes form a family of plant-specific HOMEODOMAIN transcription factors, the members of which play important developmental roles in a diverse range of processes. WOX genes were first identified as determining cell fate during embryo development, as well as playing important roles in maintaining stem cell niches in the plant. In recent years, new roles have been identified in plant architecture and organ development, particularly at the flower level. In this review, the role of WOX genes in flower development and flower architecture is highlighted, as evidenced from data obtained in the last few years. The roles played by WOX genes in different species and different flower organs are compared, and differential functional recruitment of WOX genes during flower evolution is considered. This review compares available data concerning the role of WOX genes in flower and organ architecture among different species of angiosperms, including representatives of monocots and eudicots (rosids and asterids). These comparative data highlight the usefulness of the WOX gene family for evo-devo studies of floral development.

Biological pattern and transcriptomic exploration and phylogenetic analysis in the odd floral architecture tree: Helwingia willd.

BackgroundOdd traits in few of plant species usually implicate potential biology significances in plant evolutions. The genus Helwingia Willd, a dioecious medical shrub in Aquifoliales order, has an odd floral architecture-epiphyllous inflorescence. The potential significances and possible evolutionary origin of this specie are not well understood due to poorly available data of biological and genetic studies. In addition, the advent of genomics-based technologies has widely revolutionized plant species with unknown genomic information.ResultsMorphological and biological pattern were detailed via anatomical and pollination analyses. An RNA sequencing based transcriptomic analysis were undertaken and a high-resolution phylogenetic analysis was conducted based on single-copy genes in more than 80 species of seed plants, including H. japonica. It is verified that a potential fusion of rachis to the leaf midvein facilitates insect pollination. RNA sequencing yielded a total of 111450 unigenes; half of them had significant similarity with proteins in the public database, and 20281 unigenes were mapped to 119 pathways. Deduced from the phylogenetic analysis based on single-copy genes, the group of Helwingia is closer with Euasterids II and rather than Euasterids, congruent with previous reports using plastid sequences.ConclusionsThe odd flower architecture make H. Willd adapt to insect pollination by hosting those insects larger than the flower in size via leave, which has little common character that other insect pollination plants hold. Further the present transcriptome greatly riches genomics information of Helwingia species and nucleus genes based phylogenetic analysis also greatly improve the resolution and robustness of phylogenetic reconstruction in H. japonica.

Optimization of fragrance extraction: Daytime and flower age affect scent emission in simple and double narcissi

The fragrance of Narcissus flowers is used for luxury perfumes because of its delicate odor. Fragrance productivity is relatively low and an increase in fragrance yield is therefore an important issue. This study investigated the development of scent emission and scent profile of narcissus cultivars of simple and double flower architecture. Headspace solid-phase microextraction (HS-SPME) and capillary gas chromatography/mass spectrometry (GC–MS) were applied to analyze flower scent in dependence of daytime and flower age. The major scent compounds identified were those typical for Narcissus species, monoterpenes and benzenoids, here in form of cis-β-ocimene and benzyl acetate. The double flower cultivar, with 11 major compounds had a more complex scent profile than the simple flower cultivar with 6 major volatiles. Both cultivars showed circadian emission patterns and produced significantly less scent during the night than during the day with a reduction of 40% in double flowers and 37% in single flowers. Four-day old flowers produced 37% and 59% less volatiles in double and simple flowers compared to freshly cut flowers. Volatile composition varied among cultivars, daytime and flower age, however benzyl acetate and cis-β-ocimene continuously formed the major compounds. Compound flowers with doubled perianth structures produced double amount of scent compared to simple flowers independent of daytime. The drastic differences in volatile production depending on daytime, flower age and flower architecture should be taken into account when using narcissus flowers for the production of absolute fragrance extracts.

Two tobacco AP1-like gene promoters drive highly specific, tightly regulated and unique expression patterns during floral transition, initiation and development

The genetic engineering of agronomic traits requires an array of highly specific and tightly regulated promoters that drive expression in floral tissues. In this study, we isolated and characterized two tobacco APETALA1-like (AP1-like) promoters (termed NtAP1La and NtAP1Lb1) in transgenic plants using the GUS reporter system, along with tissue-specific ablation analyses. Our results demonstrated that the two promoters are active in floral inflorescences but not in vegetative apical meristems or other vegetative tissues, as reflected by strong GUS staining and DT-A-mediated ablation of apical shoot tips during reproductive but not vegetative growth. We also showed that the NtAP1Lb1 promoter was more active than NtAP1La in inflorescences, as the former yielded higher frequencies and greater phenotypic evidence of tissue ablation compared to the latter. We further revealed that both promoters were uniformly expressed in the meristems of stage 1 and 2 floral buds, but were differentially expressed in floral organs later during development. While NtAP1La was found to be active in stage 4-5 carpels, later becoming confined to ovary tissue from stage 9 onwards, NtAP1Lb1 activity was apparent in all floral organs from stages 3 to 7, becoming completely absent in all floral organs from stage 11 onward. Therefore, it seems that the two tobacco promoters have acquired similar but distinct inflorescence-, floral meristem- and floral organ-specific and development-dependent regulatory features without any leaky activity in vegetative tissues. These features are novel and have rarely been observed in other flower-specific promoters characterized to date. The potential application of these promoters for engineering sterility, increasing biomass production and modifying flower architecture, as well as their putative use in flower-specific transgene excision, will be discussed.

An APETALA3 homolog controls both petal identity and floral meristem patterning in Nigella damascena L. (Ranunculaceae)

Flower architecture mutants provide a unique opportunity to address the genetic origin of flower diversity. Here we study a naturally occurring floral dimorphism in Nigella damascena (Ranunculaceae), involving replacement of the petals by numerous sepal-like and chimeric sepal/stamen organs. We performed a comparative study of floral morphology and floral development, and characterized the expression of APETALA3 and PISTILLATA homologs in both morphs. Segregation analyses and gene silencing were used to determine the involvement of an APETALA3 paralog (NdAP3-3) in the floral dimorphism. We demonstrate that the complex floral dimorphism is controlled by a single locus, which perfectly co-segregates with the NdAP3-3 gene. This gene is not expressed in the apetalous morph and exhibits a particular expression dynamic during early floral development in the petalous morph. NdAP3-3 silencing in petalous plants perfectly phenocopies the apetalous morph. Our results show that NdAP3-3 is fully responsible for the complex N. damascena floral dimorphism, suggesting that it plays a role not only in petal identity but also in meristem patterning, possibly through regulation of perianth organ number and the perianth/stamen boundary.

AFLP-based genetic mapping of the "bud-flowering" trait in heather (Calluna vulgaris).

BackgroundCalluna vulgaris is one of the most important landscaping plants produced in Germany. Its enormous economic success is due to the prolonged flower attractiveness of mutants in flower morphology, the so-called bud-bloomers. In this study, we present the first genetic linkage map of C. vulgaris in which we mapped a locus of the economically highly desired trait “flower type”.ResultsThe map was constructed in JoinMap 4.1. using 535 AFLP markers from a single mapping population. A large fraction (40%) of markers showed distorted segregation. To test the effect of segregation distortion on linkage estimation, these markers were sorted regarding their segregation ratio and added in groups to the data set. The plausibility of group formation was evaluated by comparison of the “two-way pseudo-testcross” and the “integrated” mapping approach. Furthermore, regression mapping was compared to the multipoint-likelihood algorithm. The majority of maps constructed by different combinations of these methods consisted of eight linkage groups corresponding to the chromosome number of C. vulgaris.ConclusionsAll maps confirmed the independent inheritance of the most important horticultural traits “flower type”, “flower colour”, and “leaf colour”. An AFLP marker for the most important breeding target “flower type” was identified. The presented genetic map of C. vulgaris can now serve as a basis for further molecular marker selection and map-based cloning of the candidate gene encoding the unique flower architecture of C. vulgaris bud-bloomers.

INTERSPECIFIC POLLEN TRANSFER AMONG CO-OCCURRING HETEROMORPHIC AND HOMOMORPHIC SPECIES

ABSTRACT Pollen transfer, and hence sharing of pollinators, among Primula veris, Narcissus assoanus, and Potentilla tabernaemontani in Northern Spain is demonstrated in the study of pollen loads on their stigmas. The length of style in both P. veris and N. assoanus is dimorphic (the former being a typical distylous species); they resemble each other in flower morphology (narrow-tubed), color, and nectar characteristics. Therefore, interspecific pollen transfer between these two species shows a pattern related to these similarities. It is inferred that the pattern of interspecific pollen transfer is mediated mainly by long-tongued pollinators seeking nectar, and that of intraspecific pollen transfer by long- and short-tongued pollinators feeding on nectar and pollen, respectively. The floral features of P. tabernaemontani are markedly different, especially in flower architecture (open) and reward (pollen). Accordingly, pollen transfer to other species is reduced, the long-styled flowers of N. assoanus bein...